The present invention relates to a structure for transmitting high mechanical stresses, said structure having an elongate core, which includes at least one rod made of agglomerated fibres, and at least one fixing means fixed to an end of the core, said fixing means including a casing and a wedging member itself located on the core and positioned within the casing. The wedging member is flared on either side of an intermediate zone thereof, so as to exert radial compression or jamming stresses on the rod in the casing and to maintain these stresses at least partially in a zone of the structure located in the casing, even when the structure is not subjected to any mechanical loading. Such a structure is described in the applicant's U.S. Pat. No. 4,057,687 patented on Nov. 8, 1977.
When it is required to use such a structure not for vertical suspension, in which case said structure is subjected mainly to traction stresses, but in an application in which the fixing means constitutes a cantilever support, in which case the structure is subjected mainly to bending moments, the design of a structure such as described in the aforementioned patent must be modified because of the high stresses applied to the rod in the fixing means. Such stresses can cause failure because of the fibrous structure of said rod.
Although the aforementioned patent relates particularly to suspension type electric insulators, high bending strength is required more particularly in fixed end beam type insulators such as those commonly called line-post insulators. For example, in practice, an insulator 1700 mm long, mounted as a fixed end beam with its axis inclined at 12.degree. with respect to the horizontal, is required to withstand a vertical load at its free end of 500 DaN.
The present invention modifies the structure described in the aforementioned patent so as to make it more resistant to high bending moments.